Lena turns around and, miraculously, Kane (Oscar Isaac) stands there, but it quickly becomes apparent that something is amiss. He begins to shudder, and while en route to the hospital the ambulance transporting him and Lena is overtaken by a military force. Lena is sedated, and when she awakens she finds herself in a mysterious compound, with her husband in a coma and suffering from organ failure. She is questioned by Dr. Ventress (Jennifer Jason Leigh), a psychologist. She learns that the compound has been established just on the outside of a phenomenon that has come to be known as the "Shimmer." In an earlier scene, we saw a meteor strike a lighthouse; the Shimmer has grown from that. Only one person has returned from previous expeditions into the Shimmer - Lena's husband Kane. No one knows exactly what is happening inside the Shimmer; they only know that it is expanding. They suspect this is not a good thing.
Lena meets three women at the compound - a physicist (Josie), a paramedic (Anya), and a geologist (Cass). She learns that they, along with Dr. Ventress, are to be the next expedition into the Shimmer. Lena joins them, and together the five women venture into the unknown. What they find is that within the Shimmer, no life is the same as it was before. Plant life is different, animal life is different (some animals are benevolent and even beautiful, others are vicious and life threatening), and there is life that doesn't look like anything that anyone has seen before.
Within a short period of time, the women realize that they are changing as well. In one sense, the trek through the Shimmer is a journey into the heart of darkness. In another sense, it is a journey of discovery. Not all of the discoveries are pleasant, and some are quite horrible. Left open to interpretation are some pretty fundamental questions that linger with the viewer after the end of the movie:
* Have these five women somehow been "chosen" for the journey?
* We learn through the story that each of them is damaged in some way - does that impact their fate within the Shimmer?
* What exactly is the ultimate fate of Lena and Kane? Are the life forms that we see at movie's end actually Lena and Kane?
* Is the film as a whole a commentary on disease? On what humans are doing to the planet we live on? On what humans do to themselves in their most self-destructive moments?
The great thing about great science fiction is that the stories can be read as an open book, by which I mean that they're like those old assignments when the teacher would read a story and then you were tasked with writing (or talking about) the ending that you thought made the most sense. "Annihilation" is clearly not for everyone, and at some points (especially the part that takes place within the lighthouse) I'm not sure I ever understood everything that was going on.
Kudos to director Alex Garland for his steady and confident hand, kudos to producer Scott Rudin for supporting his director and insisting that Paramount release the movie as Garland had intended it to be seen, and kudos to the five actresses who give the story its heart and soul: Natalie Portman, Jennifer Jason Leigh, Gina Rodriguez, Tessa Thompson, and Tuva Novotny.
